1 Answer
1

I think it is due to the fact Dio was dead and utterly destroyed, the blood was just "normal" blood without any immortal vampiric properties. Plus it is technically not Dio's blood but Jonathan Joestar's.

Jonathan's body was completely taken over by Dio and over the years it became Dio's body. Remember at first, Dio was having trouble healing his scar on his neck because the body was rejecting him, but after a couple years he completely healed and at that point he completely took over Jonathans Body. So it was in fact DIo's blood
– RumpelstiltskinJan 14 at 3:22